---
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# * Nicolas Paul
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title: Starlark
description: |
    Starlark is a dialect of Python designed for use as an efficient and
    powerful configuration language with safety and simplicity in mind.
---

# Starlark Configuration Language

**Starlark**, formerly known as *Skylark*, is a configuration language designed
at Google for simplicity, safety and expressivity. Starlark is a dialect of
Python, removed of some Turing-completness for safety.

Starlark is commonly used within [Bazel](https://bazel.build) and
[Drone](https://drone.io/).
The design choices behind Starlark ensures multiple neat properties to the
language and, by extension, to the configurations you write: determinism,
hermeticity, parallelism, and simplicity.

Here is an exemple of a Starlark code (courtesy of [Bazel's Starlark repository](https://github.com/bazelbuild/starlark?tab=readme-ov-file#tour)):

```python
# Define a number
number = 18

# Define a dictionary
people = {
    "Alice": 22,
    "Bob": 40,
    "Charlie": 55,
    "Dave": 14,
}

names = ", ".join(people.keys())  # Alice, Bob, Charlie, Dave

# Define a function
def greet(name):
    """Return a greeting."""
    return "Hello {}!".format(name)

greeting = greet(names)

above30 = [name for name, age in people.items() if age >= 30]
print("{} people are above 30.".format(len(above30)))

def fizz_buzz(n):
    """Print Fizz Buzz numbers from 1 to n."""
    for i in range(1, n + 1):
        s = ""
        if i % 3 == 0:
            s += "Fizz"
            if i % 5 == 0:
                s += "Buzz"
                print(s if s else i)

fizz_buzz(20)
```

## Implementations

SVGU is build upon the Go implementation of Starlark, but other exists.
We encourage the adoption of Starlark everywhere.

- [Go](https://github.com/google/starlark-go/)
- [Java (Bazel)](https://github.com/bazelbuild/bazel/tree/master/src/main/java/net/starlark/java)
- [Rust](https://github.com/facebookexperimental/starlark-rust)

See the [Starlark repository](https://github.com/bazelbuild/starlark/blob/master/users.md)
for a list of Bazel tools, users, and more.